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fuel octane

Discussion in 'Performance and Tuning' started by turk, Feb 14, 2021.

  1. Feb 15, 2021 at 8:53 PM
    #31
    DVCNick

    DVCNick New Member

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    They are tuned and designed for 87 E10 or flex as the case may be.
    Any additional octane is a waste of money, as is seeking out E0.

    Assuming stock motor obviously.
     
  2. Feb 16, 2021 at 9:59 AM
    #32
    dirtydeeds

    dirtydeeds Exhaust Fabricator Vendor

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    Give Keith Carty of Dirty Deeds Industries a call at 760-877-4234. He uses a different mix in each truck. He really has advanced knowledge on what you can and can't do as far as fuel is concerned.
     
  3. Feb 18, 2021 at 12:14 PM
    #33
    mass-hole

    mass-hole New Member

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    Unless Toyota simply restricted the timing on the FFV motor, E85 and higher octanes should absolutely increase power. Otherwise, what would be the point? They should be able to run the engine a MBT with E85 without issue. Even Ecoboosts with 10.5:1 compression ratios and 20+ lbs of boost are able to run at MBT on E85.

    GM says that the 5.3L V8 goes from 355hp/380tq to 380hp/416tq on E85 in stock form.
     
  4. Feb 18, 2021 at 12:19 PM
    #34
    AZTundra

    AZTundra No Longer a New Member

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    Supercharged and run 91 octane (highest available here). Truck seems to run best with QT fuel, so I stick with that.
     
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  5. Feb 18, 2021 at 12:31 PM
    #35
    DVCNick

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    Stock, the point is to just be able to run what's available.
    To make more power on E85, or even 93, in all likelihood you will need aftermarket tuning at a minimum, and more likely forced induction.

    But... if they did tune for a different power level on E85, which I've never heard before, you can bet that the bigger number will be advertised as "the spec". So you'd have less power than advertised on 87 if that's what they did.

    Any all-stock dyno runs back to back out there? That is the only thing that really matters.
     
  6. Feb 18, 2021 at 12:40 PM
    #36
    prevent

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    Would anyone buy a truck that listed Premium fuel as a requirement when it isn’t even supercharged?

    There’s another thread on here about Octane and it sounded like the truck can use 87 just fine, but it retards the timing to do so. The idea is that Toyota only lists 87 because when shoppers comparing trucks that are otherwise identical, the one that requires more expensive fuel wouldn’t sell very well.

    I’m thinking that higher octane fuel probably does help the engine produce more power, but the difference is so small on a stock truck that it’s probably on par with other factors like ambient air temp.

    I personally run premium, the price difference can be reduced significantly by combining a gas station’s customer rewards program with a cash-back credit card (Exxon + Apple Pay in my case). Or maybe that’s just how I justify it to myself, lol.

    I wish I could run ethanol free but that’s a no-go in my area. I’ve heard people say that some brands use less ethanol in their premium blends but who knows.
     
  7. Feb 18, 2021 at 12:43 PM
    #37
    DVCNick

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    If it was tuned for 93, it would make a little more power on 93, and it would likely have to pull timing to protect itself in hot/high rpm/etc situations with 87.

    But if the manual says 87, it will run best on 87 and if anything will make more power on 87 than 93. If the manual says 87, you aren't doing anything but spending more money with 93.
     
    Yotaholic and Cpl_Punishment like this.
  8. Feb 18, 2021 at 12:44 PM
    #38
    Leo's first

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    The salesman recommended to run E85 in a non flex fuel truck?
     
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  9. Feb 18, 2021 at 1:47 PM
    #39
    Nick T

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    Toyota ECU will constantly advance timing until it hears detonation/knock.
    If you run premium you will generally get more power as it is less likely to knock vs 87 octane.
    The truck will run fine on 87, it will just not advance timing as much as on 91/93

    Note Toyota rates their engines on 87 and Lexus rates their engines on 91
    Lexus engines will be advertised with a higher HP even when they are the exact same engine. Land Cruiser / LX570
     
    MTRock likes this.
  10. Feb 18, 2021 at 3:43 PM
    #40
    mass-hole

    mass-hole New Member

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    This. Right here. They design the engine to run on 87 because its cheaper. That does not mean the PCM cannot take advantage of higher octanes. Every manufacturer does this because, if they didnt, they are leaving MPG's on the table. EPA MPG estimates are made on 91 octane BTW.

    A Ford 3.5L Ecoboost, for example, says it can be run on 87 in the owners manual. But they can pick up 30 RWHP just from switching from 87 to 93 on the stock tune. Just because it can run on 87 does not make it optimal.

    My lexus has a "Knock Correction" PID that I monitor through the OBDLink app. It is the value that the PCM uses to calibrate the ignition timing based on the long term performance of the fuel. If the fuel sucks that value reduces and you get less timing advance. If its good fuel, it increases and give you more timing.

    GM does recommend running 91 octane all the time on their 6.2L though. The 5.3L has a lower compression ratio so it runs fine on 87.

    And with regards to the Toyota motors, my GX has the same 1UR 4.6L as the Tundra once did. Spec for spec. Yet the tundra is ok to run 87 while my GX is supposed to run 91? The GX can absolutely run 87 and plenty of people do. No one has burnt a hole thought their piston yet.
     
  11. Feb 18, 2021 at 3:52 PM
    #41
    DVCNick

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    The top hp number with the stock tune is going to be at the lowest octane recommended in the manual, or they would recommend higher grade fuel and advertise a bigger hp number. (For the post above... I'm sure the Ecoboost recommends 93. 87 will be for when you can't get 93, and you'll be able to run it, but will get less than the factory rated power, and rely on modern computers being smart enough to make the changes necessary to not damage the motor)

    Show me the dynos if you think differently. I'm open to being proven wrong. :) But this is how it works.

    E85 is basically government subsidized race gas, equivalent to a much higher octane number. Great for forced induction guys; with a stock truck I don't see any reason to use it unless it is all that's available. Unless you have a motor built and tuned to take advantage of it, you will get less mileage and probably less power.
     
    Last edited: Feb 18, 2021
    Cpl_Punishment likes this.
  12. Feb 18, 2021 at 7:21 PM
    #42
    Yotaholic

    Yotaholic Amateur Professional

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    I about freaked out until I saw your next post stating your truck was a FlexFuel model...lol. That would have been worth mentioning!

    E85 will driver terrible fuel mileage but it’s usually super cheap fuel so that’s how it’s justifiable. It depends on how expensive E10 is to actually make the price and MPG difference work out in your favor.

    21MPG in a Tundra is impressive!
     
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  13. Feb 18, 2021 at 7:35 PM
    #43
    Leo's first

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    E85 is almost impossible to find around here
    I’ve only seen it at Logan airport and one other place in Boston it’s 30-60 cents higher then regular
     
  14. Feb 19, 2021 at 8:06 AM
    #44
    iDon’tRead

    iDon’tRead New Member

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    91 is the only choice for ethanol free here in Minnesota for the fuel stations around me .. looks like I’m going premium
     
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  15. Feb 19, 2021 at 9:00 AM
    #45
    mass-hole

    mass-hole New Member

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    The normal Ecoboost is not rated on 93. It is rated on 87. The Raptor, Lincoln Navigator, and F150 Limited with the 3.5 HO motor were rated on 93 and had footnotes plastered all over their website stating as such. Additionally, The Expedition Limited got the regular Ecoboost but had power ratings bumped to 400hp/500 tq(from 375/470) because they rated it on 93. Same goes for the 2.3L Ecoboost in the ranger. It is rated on 87 while the mustang is rated on 93 and has higher factory output on basically the same motor.

    Toyota would be incredibly stupid if they limited timing to the max possible at 87 octane and left zero margin for octane or even changes in environmental conditions.
     
    Last edited: Feb 19, 2021

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